Whales are a diverse group of animals – and yes, whales are mammals. They breathe air (through blowholes), and in fact, some whales are even identified by the characteristic shapes of their spray. Female whales give birth to live young who they feed with milk. All whales are warm blooded, and they eat and make blubber to stay warm as they move through the world's huge oceans.
Because of their diversity, each species has a life cycle that is a bit different.
What's a Baleen?
There are two main groups of whales (taxonomic order Cetacea): baleen whales and toothed whales. Toothed whales, like killer whales, dolphins and narwhals, sometimes have teeth they use to devour larger prey. However, their name can be misleading; sometimes those teeth aren't very sharp, or the whale species in question doesn't have many teeth. Toothed whales only have one blowhole.
Baleen whales have mouths full of baleen plates instead of teeth. These allow them to filter the water and eat large amounts of small critters like crustaceans and plankton. Baleen whales breathe through paired blowholes.
Toothed or baleen, whales are amazing. Some whales have a life span similar to humans – around 80 or 90 years. The largest creature on Earth, the blue whale, can grow large enough to fit in an Olympic-sized swimming pool with only a few feet to spare.
Like most animals on the planet, whales find a mate by courting. Males show off with song, fancy swimming or even gift giving. Females often mate with more than one male each season. Depending on the species, a calf can take 10 to 17 months to develop in its mother's womb. Mothers make a thick milk that won't dissipate easily in the ocean water.
Some baby whales, also known as calves, stay with their mother and original pod for life; others will travel alone or find a new pod once they are independent hunters and swimmers.
Read more about how whale's mate.
Life Cycle of a Gray Whale
Gray whales are a common sight off the West Coast of the United States.
They are dark gray in color, but often splotched with white. These patches are barnacles, a creature that seems to make a happy home on the gray whale. A thorough covering of barnacles can indicate an older whale. Gray whales are often solitary or travel in small groups. Gray whales are only found in the Pacific Ocean.
Off the United States, they feed in northern waters in the summer, and in the fall, they migrate south to Baja California. At around eight years old, mothers are able to give birth to one calf.
Life Cycle of a Killer Whale
Also known as orcas, killer whales are arguably the easiest type of whale to identify.
They have sleek black bodies with tall, straight dorsal fins and white patches behind their eyes and on their undersides. An orca's diet is diverse and depends on their habitat. In the North Pacific, orcas seem to prefer salmon and other fish. Elsewhere, they have been known to eat squid, sea lions and other small marine mammals, and seabirds like penguins. As their nickname suggests, killer whales are accomplished hunters, often working together to trap prey.
Read more about a whale's diet.
They spend their 50 to 60 years of life with a pod of about 20 other whales. At age 10 to 13, female orcas can get pregnant. They can birth one calf at a time. Moms will nurse their young for one year.
Life Cycle of a Humpback Whale
Each year humpback whales migrate from the tropics, where they breed, to more abundant feeding grounds in the higher latitudes. Some humpbacks migrate up to 5,000 miles. In colder waters, they devour krill and small fish by filtering them through their baleen plates. Humpbacks are easy to identify due to a unmistakeable hump in front of their dorsal fin, long pectoral fins and white undersides. Some humpbacks are able to give birth starting at age four.
Mothers have one calf that they will nurse for a year. Though calves are thought to return to the same breeding and feeding grounds as their moms, they usually don't stick together for life. Humpbacks can live up to 90 years.
About the Author
Emily Bornhop is a marine biologist taking a break from life at sea. She has worked in science publishing, science education and, of course, the laboratory.
Image by Flickr.com, courtesy of Richard Fisher